On Sat, 26 Feb 2005 14:41:45 +0000, Dave Arquati wrote:

Paul Corfield wrote:
On Fri, 25 Feb 2005 13:29:34 +0000, Dave Arquati wrote:

The card will store 10 journeys worth of information. Therefore it is
updated each time there is a transaction such as an entry at a gate or
tapping your card on a bus reader. Both the card and reading device
exchange information and validity checks are made. There is a
transaction written to the card and also one generated in the reading /
checking device. As the conductor machine can deduct cash as well as
sell a paper ticket then it MUST record all transactions - how else is
the money accounted for?

I realise the conductor's machine must record the transactions, but the
station ticket machine also showed Ian's bus journey straight away. Does
it only read the information from the card, or does it also synchronise
with the central database - or is that left to the update from the
conductor's machine only?

As I understand it the station machine only reads the card - hence why
only 10 journeys can be displayed. If the central system had to be
interrogated every time then the system traffic would be huge for little
purpose. Transactions would take longer at ticket machines as well.

The central system can only synchronise with the card overnight because
it is entirely possible for some of the transactions that need to reach
the central system are still on a vehicle somewhere.

I also presume some new software had to be downloaded into every single
Oyster reader for the introduction of capping - I wonder whether this
has been done in advance with it only becoming "switched on" tomorrow?

Again I'm not totally sure how it works on the bus side of things but
certainly the LUL system allows advance loading and then timed
activation. Advance downloading would be the most sensible thing to do
or else you end having to physically attend to each ETM and thus risk
reducing bus availability. The bus operators hate things like that as it
puts them at risk of penalties for late or cancelled journeys. It's also
a very expensive way of undertaking modifications.
--
Paul C


Admits to working for London Underground!